Heparin Induced Antibody, HIT, PF4
Note: Testing will not be performed if patient has platelet counts >= 150,000. Testing will be paused, the sample will be held for 5 days, after which testing will be cancelled and credited. Please contact the lab for approval for testing of patients without thrombocytopenia.
Diagnosing heparin-induced thrombocytopenia.
Collect two citrated Blue Top Tubes (BTT) to make two 1.0 mL platelet poor plasma aliquots
If other coagulation testing is ordered, separate aliquots are needed for each individual test
Citrate anticoagulant must be adjusted for HCT >55%
Tube must be at least 90% full
Invert completely 3-4 times (without shaking) to mix
*See Instructions for: Preparation of Platelet Poor Plasma
Monday through Friday - twice per day
Weekends/Holidays - as needed
Less than 2 hours
Negative: This result has approximately 90-95% negative predictive value for excluding heparin-induced thrombocytopenia (HIT)
Positive: Heparin dependent antibodies are present. This result has a reasonably good correlation with the serotonin release assay (SRA). Serotonin Release Assay (SRA) has been ordered and will be performed by Versiti. Results should be available within 2-3 days. If the clinical situation warrants, initiating treatment for heparin-induced thrombocytopenia (HIT) is reasonable.